Cannot change icons or icon overlay in windows 10

I've read several posts regarding icon changing and icon overlaying on Windows and download 3-4 code projects that handle this issue, but unfortunately none of them worked. What I'm trying to do is just as simple as it sounds - 1. change icon of a specific file when an event occurs through my system. 2. overlay icon of a specific file when an event occurs through my system.

For example: 1. I tried to use the following c++ project -

https://www.codeproject.com/Articles/797/The-Complete-Idiots-Guide-to-Writing-Shell-Exten-9

I have managed to compile it and add my logics, but it's never worked for me (even going back to the original project didn't work).

2. I also tried to use the code posted here: Icon overlay in c#

but also in this case nothing worked and the icons were neither changed nor overlayed.

In both ways (and in many others) the relevant registry entries were created and updated as expected, however no icon was changed.

I also of course tried all the Clear Cache ways but it had no effect.